Neuro-Ophthalmology — MCQs
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A 40-year-old female presented with an excruciating headache, ptosis, downward and outward gaze of the eyeball, and a large pupil. She also complained of blurred and double vision. An magnetic resonance angiogram scan showed an aneurysm of the circle of Willis. Which artery gives rise to the offending aneurysm?
Which of the following drugs does NOT cause retinal changes?
Internuclear ophthalmoplegia is caused due to a lesion in which of the following?
Papilledema is caused by tumors arising from all the following structures except:
Anisocoria in dim light is maximally seen in which condition?
All of the following findings are associated with optic neuritis except?
A 23-year-old woman complains of progressive loss of vision and papilledema. Investigations show normal findings on CT scan. A lumbar puncture shows marked elevation of pressure. What is the most likely diagnosis?
Diagnose the ocular pathology.
Opsoclonus is a feature of which of the following conditions?
Which of the following is NOT a feature of Horner syndrome?
Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs
Question 81: A 40-year-old female presented with an excruciating headache, ptosis, downward and outward gaze of the eyeball, and a large pupil. She also complained of blurred and double vision. An magnetic resonance angiogram scan showed an aneurysm of the circle of Willis. Which artery gives rise to the offending aneurysm?
- A. Anterior choroidal artery
- B. Anterior communicating artery
- C. Charcot-Bouchard's artery
- D. Posterior communicating artery (Correct Answer)
Explanation: **Explanation:** The clinical presentation describes a classic **Third Nerve Palsy (Oculomotor Nerve)**. The combination of ptosis (levator palpebrae superioris), "down and out" gaze (unopposed action of Superior Oblique and Lateral Rectus), and a dilated, non-reactive pupil (loss of parasympathetic fibers) indicates a **surgical third nerve palsy**. **Why the Posterior Communicating Artery (PComA) is correct:** The Oculomotor nerve (CN III) passes directly between the Posterior Cerebral Artery and the Superior Cerebellar Artery, running parallel and lateral to the **Posterior Communicating Artery**. An aneurysm at the junction of the Internal Carotid Artery and PComA is the most common cause of a pressure-induced (compressive) third nerve palsy. Because the parasympathetic pupilloconstrictor fibers are located superficially (peripherally) on the nerve, they are the first to be compressed, leading to a **dilated pupil**. **Why the other options are incorrect:** * **Anterior Choroidal Artery:** While it arises near the PComA, it does not have the same close anatomical relationship with the third nerve. * **Anterior Communicating Artery:** Aneurysms here typically cause visual field defects (bitemporal hemianopia) due to proximity to the optic chiasm, not third nerve palsy. * **Charcot-Bouchard’s Artery:** These are small lenticulostriate arteries involved in hypertensive intracerebral hemorrhages (usually in the basal ganglia), not large aneurysms causing cranial nerve compression. **High-Yield Clinical Pearls for NEET-PG:** 1. **Rule of Pupil:** In CN III palsy, if the pupil is **involved** (dilated), suspect a **compressive lesion** (e.g., PComA aneurysm). If the pupil is **spared**, suspect a **medical/ischemic cause** (e.g., Diabetes Mellitus). 2. **Emergency:** A painful third nerve palsy with pupillary involvement is a neurosurgical emergency until a PComA aneurysm is ruled out. 3. **Nerve Course:** CN III exits the midbrain in the interpeduncular fossa.
Question 82: Which of the following drugs does NOT cause retinal changes?
- A. Tamoxifen
- B. Amiodarone (Correct Answer)
- C. Hydroxychloroquine
- D. Vigabatrin
Explanation: **Explanation:** The correct answer is **Amiodarone**. In neuro-ophthalmology and ocular pharmacology, it is crucial to distinguish between drugs that affect the **retina** and those that affect the **cornea or optic nerve**. **1. Why Amiodarone is the correct answer:** Amiodarone is classically associated with **Vortex Keratopathy (Cornea Verticillata)**—fine, whorl-like golden-brown deposits in the basal epithelium of the **cornea**. While it can rarely cause optic neuropathy, it does **not** typically cause retinal pigmentary changes or retinal toxicity. **2. Analysis of Incorrect Options (Drugs causing Retinal changes):** * **Tamoxifen:** Used in breast cancer treatment, it causes **Tamoxifen Retinopathy**, characterized by bilateral, fine, yellow, crystalline deposits in the macula (paramacular area) and cystoid macular edema. * **Hydroxychloroquine (HCQ):** A high-yield topic. It causes **"Bull’s Eye Maculopathy"** due to the drug binding to melanin in the Retinal Pigment Epithelium (RPE). Screening with 10-2 Visual Fields and SD-OCT is mandatory for long-term users. * **Vigabatrin:** An antiepileptic drug known for causing **permanent peripheral visual field constriction** due to localized retinal toxicity (specifically affecting the photoreceptors and ganglion cells). **Clinical Pearls for NEET-PG:** * **Cornea Verticillata Mnemonic:** "**C**hloroquine, **A**miodarone, **I**ndomethacin, **T**amoxifen" (**CAIT**) and **Fabry’s disease**. * **Bull’s Eye Maculopathy Differential:** HCQ toxicity, Stargardt’s disease, Cone-Rod dystrophy, and Benign Concentric Macular Dystrophy. * **Thioridazine & Chlorpromazine:** Other psychiatric drugs that cause pigmentary retinopathy (salt and pepper appearance).
Question 83: Internuclear ophthalmoplegia is caused due to a lesion in which of the following?
- A. Occipital lobes
- B. Pretectal fibres
- C. Medial longitudinal fasciculus (Correct Answer)
- D. Para pontine reticular fibres
Explanation: **Explanation:** **Internuclear Ophthalmoplegia (INO)** is a classic neuro-ophthalmological syndrome characterized by an impairment of horizontal conjugate gaze. **1. Why Medial Longitudinal Fasciculus (MLF) is correct:** The MLF is a heavily myelinated nerve tract that connects the **Abducens nucleus (CN VI)** on one side of the pons to the **contralateral Oculomotor nucleus (CN III)** in the midbrain. For horizontal gaze, the Abducens nucleus triggers the lateral rectus (abduction) and simultaneously sends a signal through the MLF to the opposite Medial Rectus subnucleus to trigger adduction. A lesion in the MLF disrupts this communication, leading to: * **Ipsilateral failure of adduction** (the eye on the side of the lesion cannot move inward). * **Contralateral abducting nystagmus** (a compensatory mechanism in the healthy eye). **2. Why other options are incorrect:** * **Occipital lobes:** Responsible for visual processing and perception, not the coordination of extraocular muscle nuclei. * **Pretectal fibers:** Involved in the pupillary light reflex pathway (e.g., Parinaud syndrome). * **Para pontine reticular formation (PPRF):** This is the "horizontal gaze center." A lesion here causes **horizontal gaze palsy** (neither eye can look toward the side of the lesion), unlike INO where abduction is preserved. **Clinical Pearls for NEET-PG:** * **Etiology:** In young adults, the most common cause is **Multiple Sclerosis** (often bilateral). In elderly patients, it is usually a **Vascular stroke** (often unilateral). * **Convergence:** In a posterior MLF lesion, convergence is typically **preserved** because the pathway for convergence bypasses the MLF. * **One-and-a-half Syndrome:** Caused by a combined lesion of the PPRF (or Abducens nucleus) and the MLF on the same side.
Question 84: Papilledema is caused by tumors arising from all the following structures except:
- A. Cerebrum
- B. Cerebellum
- C. Thalamus
- D. Medulla (Correct Answer)
Explanation: **Explanation:** **Papilledema** is defined as passive swelling of the optic disc due to **increased intracranial pressure (ICP)**. The fundamental mechanism involves the transmission of high CSF pressure through the subarachnoid space surrounding the optic nerve, which leads to the stasis of axoplasmic flow at the lamina cribrosa. **Why Medulla is the Correct Answer:** Tumors of the **Medulla** (lower brainstem) are generally less likely to cause papilledema compared to other locations. This is because the medulla is situated in the lower part of the posterior fossa, near the foramen magnum. Tumors here often present with cranial nerve palsies or respiratory/cardiac center disturbances before they can cause a significant rise in ICP. Furthermore, they are less likely to cause an early obstruction of the ventricular system (like the Aqueduct of Sylvius), which is the primary driver for rapid ICP elevation in brain tumors. **Analysis of Other Options:** * **Cerebrum:** Large supratentorial masses (frontal, parietal, or temporal lobes) cause significant mass effect and midline shift, leading to increased ICP and papilledema. * **Cerebellum:** Tumors in the cerebellum (posterior fossa) are notorious for causing early papilledema because they compress the **fourth ventricle**, leading to obstructive hydrocephalus. * **Thalamus:** Thalamic tumors can compress the **third ventricle** or the internal cerebral veins, leading to a rapid rise in intracranial pressure. **Clinical Pearls for NEET-PG:** * **Foster Kennedy Syndrome:** Occurs with frontal lobe tumors; characterized by ipsilateral optic atrophy (due to direct compression) and contralateral papilledema (due to increased ICP). * **Early Sign:** The earliest clinical sign of papilledema is the **loss of spontaneous venous pulsations (SVP)**, though 20% of normal individuals lack SVP. * **Visual Field:** The characteristic visual field defect in early papilledema is an **enlarged blind spot**. * **Paton’s Lines:** Circumferential retinal folds seen in the temporal peripapillary region in cases of significant disc edema.
Question 85: Anisocoria in dim light is maximally seen in which condition?
- A. 3rd nerve palsy
- B. Pharmacological mydriasis
- C. Horner syndrome (Correct Answer)
- D. Parasympathetic paralysis
Explanation: **Explanation:** The key to solving anisocoria questions lies in determining whether the difference in pupil size increases in **dim light** or **bright light**. **1. Why Horner Syndrome is correct:** Anisocoria that is **more pronounced in dim light** indicates a failure of the pupil to dilate (a **sympathetic** defect). In Horner syndrome, there is a lesion in the oculosympathetic pathway, leading to miosis (constricted pupil) on the affected side. In dim light, the normal pupil dilates fully, while the Horner pupil fails to dilate, making the discrepancy between the two eyes maximal. This is often associated with a "dilation lag." **2. Why the other options are incorrect:** * **3rd Nerve Palsy & Parasympathetic Paralysis:** These involve the parasympathetic fibers responsible for constriction. Therefore, the affected pupil is abnormally large (mydriasis). The anisocoria becomes **more pronounced in bright light**, as the normal pupil constricts while the affected pupil remains dilated. * **Pharmacological Mydriasis:** This is caused by drugs (like Atropine) that block the sphincter pupillae. Similar to 3rd nerve palsy, the anisocoria is **maximal in bright light** because the medicated pupil cannot constrict. **Clinical Pearls for NEET-PG:** * **The Rule of Light:** * Anisocoria ↑ in **Dim** light = **Sympathetic** problem (e.g., Horner’s). * Anisocoria ↑ in **Bright** light = **Parasympathetic** problem (e.g., Adie’s Tonic Pupil, 3rd Nerve Palsy). * **Horner’s Triad:** Miosis, partial Ptosis (Muller’s muscle), and Anhidrosis. * **Cocaine Test:** In Horner’s, the pupil will **not** dilate after cocaine drops (confirms diagnosis). * **Apraclonidine Test:** Causes "reversal of anisocoria" (dilation) in Horner’s due to denervation supersensitivity.
Question 86: All of the following findings are associated with optic neuritis except?
- A. Painful ocular movements
- B. Defective color perception
- C. Defective depth perception
- D. Metamorphopsia (Correct Answer)
Explanation: ### Explanation **Optic Neuritis** is an inflammatory, demyelinating condition of the optic nerve, most commonly associated with Multiple Sclerosis. **Why Metamorphopsia is the Correct Answer:** Metamorphopsia (distortion of shapes/straight lines) is a hallmark symptom of **macular pathology** (e.g., Central Serous Chorioretinopathy or Age-related Macular Degeneration), not optic nerve disease. In optic neuritis, the pathology lies in the conduction of the nerve impulse, which affects clarity and brightness rather than spatial orientation or shape perception. **Analysis of Incorrect Options:** * **Painful ocular movements:** This is a classic feature (present in 90% of cases). Pain occurs because the origins of the superior and medial recti are closely attached to the sheath of the optic nerve at the orbital apex; movement stretches the inflamed sheath. * **Defective color perception:** Dyschromatopsia (specifically **red-green desaturation**) is often the first sign of optic nerve dysfunction and is frequently more severe than the loss of visual acuity. * **Defective depth perception:** Known as the **Pulfrich phenomenon**, this occurs due to delayed conduction in the affected optic nerve compared to the healthy eye, leading to a mismatch in binocular timing and altered motion/depth perception. **Clinical Pearls for NEET-PG:** 1. **Marcus Gunn Pupil:** A Relative Afferent Pupillary Defect (RAPD) is the most important objective clinical sign. 2. **Uthoff’s Phenomenon:** Transient worsening of vision with increased body temperature (e.g., after a hot bath or exercise). 3. **Fundus Findings:** In Retrobulbar Neuritis (the most common type in adults), the fundus initially appears **normal** ("The patient sees nothing, and the doctor sees nothing"). 4. **Treatment:** The **ONTT (Optic Neuritis Treatment Trial)** recommends IV Methylprednisolone to speed up recovery; oral steroids alone are contraindicated as they increase the rate of recurrence.
Question 87: A 23-year-old woman complains of progressive loss of vision and papilledema. Investigations show normal findings on CT scan. A lumbar puncture shows marked elevation of pressure. What is the most likely diagnosis?
- A. Pseudotumor cerebri (Correct Answer)
- B. Corpus cavernous thrombosis
- C. Cavernous sinus thrombosis
- D. Retinoblastoma
Explanation: ### Explanation The clinical presentation of progressive vision loss and papilledema in a young woman, combined with a normal CT scan and elevated intracranial pressure (ICP) on lumbar puncture, is the classic triad for **Pseudotumor Cerebri**, also known as **Idiopathic Intracranial Hypertension (IIH)**. **1. Why Pseudotumor Cerebri is Correct:** IIH is characterized by signs and symptoms of increased ICP (headache, papilledema, vision loss, or CN VI palsy) without an identifiable cause (like a tumor or infection). The diagnosis requires: * Symptoms of increased ICP. * Normal neuroimaging (CT/MRI) to rule out space-occupying lesions. * Elevated opening pressure on lumbar puncture (>25 cm H₂O) with normal CSF composition. **2. Why the Other Options are Incorrect:** * **Cavernous Sinus Thrombosis:** Typically presents acutely with fever, proptosis, chemosis, and painful ophthalmoplegia (involving CN III, IV, and VI). It is a life-threatening infectious/thrombotic process, not a chronic progressive vision loss with normal imaging. * **Corpus Cavernous Thrombosis:** This is a misnomer in this context; it refers to priapism in urology and has no relation to neuro-ophthalmology. * **Retinoblastoma:** A childhood retinal tumor (usually <3 years old). It presents with leukocoria (white reflex) and would be clearly visible on a CT scan or fundus examination, not as isolated papilledema with high ICP. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in **obese females** of childbearing age. * **Associated Drugs:** Remember the mnemonic **"PANTS"**: **P**henytoin/Steroid withdrawal, **A**ll-trans retinoic acid/Vitamin **A**, **N**alidixic acid, **T**etracyclines, **S**ulfa drugs. * **Visual Field:** The most common defect is an **enlarged blind spot**. * **Treatment:** Weight loss is first-line; **Acetazolamide** (carbonic anhydrase inhibitor) is the drug of choice to decrease CSF production. Surgical options include optic nerve sheath fenestration or CSF shunting.
Question 88: Diagnose the ocular pathology.
- A. Primary optic atrophy
- B. Primary open angle glaucoma
- C. Papilledema (Correct Answer)
- D. Central retinal artery occlusion
Explanation: ***Papilledema*** - Characterized by **optic disc swelling** with **blurred disc margins**, **flame-shaped hemorrhages**, and **cotton wool spots** around the optic nerve head. - Associated with **elevated intracranial pressure** causing bilateral optic disc edema with preserved **central vision** initially. *Primary optic atrophy* - Shows a **pale optic disc** with **sharp, well-defined margins** and **loss of nerve fiber layer**. - Results from **chronic optic nerve damage** with **reduced visual acuity** and **visual field defects**. *Primary open angle glaucoma* - Presents with **increased cup-to-disc ratio** (>0.5) and **vertical cupping** of the optic disc. - Characterized by **rim thinning** and **nerve fiber layer defects** without disc swelling or hemorrhages. *Central retinal artery occlusion* - Shows **cherry-red spot** at the macula with **pale, whitish retina** due to retinal ischemia. - Fundoscopy reveals **attenuated arterioles** and **absence of arterial blood flow** with sudden severe vision loss.
Question 89: Opsoclonus is a feature of which of the following conditions?
- A. Carcinoma of the lung (Correct Answer)
- B. Retinoblastoma
- C. Focal seizure with dyscognitive changes
- D. Extrapyramidal damage in Wilson's disease
Explanation: **Explanation:** **Opsoclonus** is a rare, high-frequency, involuntary, multivectorial eye movement disorder characterized by spontaneous, rapid, and chaotic "dancing eyes." It is often associated with myoclonus (Opsoclonus-Myoclonus-Ataxia Syndrome). **1. Why Carcinoma of the Lung is Correct:** In adults, opsoclonus is most commonly a **paraneoplastic manifestation**. It is frequently associated with **Small Cell Lung Carcinoma (SCLC)**, mediated by the **anti-Ri (ANNA-2)** antibody. The underlying mechanism involves an immune-mediated attack on the brainstem and cerebellum triggered by the underlying malignancy. **2. Analysis of Incorrect Options:** * **Retinoblastoma:** While a common pediatric ocular tumor, it does not cause opsoclonus. However, in children, opsoclonus is a classic paraneoplastic sign of **Neuroblastoma** (not Retinoblastoma). * **Focal seizure with dyscognitive changes:** Seizures typically present with rhythmic nystagmoid movements or tonic-clonic deviations, not the chaotic, non-rhythmic movements of opsoclonus. * **Wilson’s Disease:** Extrapyramidal damage in Wilson’s disease typically manifests as a "wing-beating" tremor, dystonia, or parkinsonism. Ocular findings include the **Kayser-Fleischer (KF) ring** and "sunflower cataracts," but not opsoclonus. **High-Yield Clinical Pearls for NEET-PG:** * **Pediatric Association:** Always rule out **Neuroblastoma** in a child presenting with "Dancing Eyes, Dancing Feet" (Opsoclonus-Myoclonus Syndrome). * **Adult Association:** Small Cell Lung Cancer (SCLC) and Breast Cancer. * **Anatomical Site:** Dysfunction is localized to the **omnipause neurons** in the nucleus raphe interpositus of the pons, which normally inhibit saccadic bursts. * **Key Antibody:** **Anti-Ri** is the most high-yield antibody associated with paraneoplastic opsoclonus.
Question 90: Which of the following is NOT a feature of Horner syndrome?
- A. Exophthalmos (Correct Answer)
- B. Ptosis of the upper eyelid
- C. Miosis
- D. Conjunctival congestion
Explanation: **Explanation:** Horner syndrome results from a lesion in the **oculosympathetic pathway**. The sympathetic nervous system is responsible for pupillary dilation, eyelid elevation, and vasoconstriction. When this pathway is interrupted, a classic triad of symptoms occurs. **Why Exophthalmos is the correct answer:** Horner syndrome actually causes **Enophthalmos** (the appearance of a sunken eye), not exophthalmos. This is a "pseudo-enophthalmos" caused by the narrowing of the palpebral fissure due to the drooping of the upper lid and slight elevation of the lower lid. Exophthalmos (protrusion of the eyeball) is typically associated with conditions like Graves' ophthalmopathy or orbital tumors. **Why the other options are incorrect:** * **Ptosis:** Occurs due to paralysis of **Müller’s muscle** (superior tarsal muscle), which is sympathetically innervated. This is a "partial ptosis" (1-2mm) compared to the complete ptosis seen in 3rd nerve palsy. * **Miosis:** The loss of sympathetic supply to the **dilator pupillae** muscle leads to an unopposed action of the sphincter pupillae (parasympathetic), resulting in a constricted pupil. * **Conjunctival Congestion:** Sympathetic nerves normally maintain vasoconstriction. Their loss leads to **vasodilation** of the conjunctival and facial blood vessels, causing redness and flushing. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Triad:** Ptosis, Miosis, and Anhidrosis (loss of sweating). 2. **Inverse Ptosis:** Elevation of the lower eyelid (due to paralysis of the inferior tarsal muscle). 3. **Cocaine Test:** In Horner syndrome, the pupil **fails to dilate** after cocaine drops. 4. **Apraclonidine Test:** Causes **reversal of anisocoria** (the Horner pupil dilates while the normal pupil remains unchanged). 5. **Heterochromia Iridum:** Seen specifically in **congenital** Horner syndrome (the affected eye is lighter).
Practice by Chapter
Anatomy of Visual Pathways
Practice Questions
Pupillary Disorders
Practice Questions
Optic Neuritis
Practice Questions
Ischemic Optic Neuropathies
Practice Questions
Other Optic Neuropathies
Practice Questions
Papilledema
Practice Questions
Cranial Nerve Palsies
Practice Questions
Nystagmus
Practice Questions
Visual Field Defects
Practice Questions
Neuro-ophthalmic Manifestations of Intracranial Lesions
Practice Questions
Functional Visual Disorders
Practice Questions
Migraine and the Eye
Practice Questions
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